Avast Endpoint Protection is supposed to be software that finds malware, not software that advises web developers on how to improve security.
AES doesn't advise developers on how to improve security, it is trying to protect systems from getting infected. Blocking/stopping malware is just one part of it. Another part (amongst many more), is preventing users to be redirect to malicious sites/files.

If other scanners don’t block things like this, it means there is room for improvement on the security they are offering.